The Effects of Advancing Gestation on Maternal Autonomic Response

Important changes occur in the maternal autonomic nervous system with advancing gestation. Tracking maternal autonomic modulation with heart rate variability (HRV) may hold opportunities for early detection of pregnancy complications such as hypertensive disorders of pregnancy (HPD) since these are associated with autonomic dysfunction. However, traditional HRV features often show conflicting trends over gestation. In this paper we implement phase rectified signal averaging (PRSA) to longitudinally track autonomic response throughout gestation. Since other fields of investigation have shown attenuated autonomic responsivity in healthy pregnancy, we hypothesized that assessing PRSA longitudinally over pregnancy would elicit a clearer trajectory of autonomic modulation. We found that autonomic responsiveness becomes significantly attenuated towards the end of pregnancy, although not to a degree that is comparable to diseased states. PRSA features show clear downward trends across pregnancy, with an uptick right before pregnancy ends, perhaps showing increased autonomic activity in preparation for delivery. We conclude that longitudinal analysis using PRSA holds promise as a potential screening tool for high-risk pregnancies.